Magnetic retaining device for electronic apparatus

ABSTRACT

A retaining device for an electronic apparatus comprising a plurality of cases respectively containing individual component mechanisms of a small electronic apparatus, a magnet disposed in a recess formed in a surface of a first case among the plurality of cases and a magnetic member provided on a second case among the plurality of cases. In this device, the magnet (60) attracts the magnetic member to fix the respective positions of the first case and the second case relative to each other when the first case and the second case are set contiguously with the magnet and the magnetic member disposed opposite to each other.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a retaining device for an electronicapparatus, used for setting an electronic apparatus, such as a personalcomputer, a word processor or a printer for a personal computer or aword processor, in an operating position.

2. Description of the Related Art

Such a small electronic apparatus has individual internal mechanismscontained respectively in a plurality of cases, and the positionsthereof relatively to each other can be changed for carrying or foroperation. The plurality of cases must be fixed relative to each other,to thereby operate the small electronic apparatus.

When fixing the plurality of cases of such a small electronic apparatusrelatively to each other, the conventional retaining device for anelectronic apparatus employs a mechanical locking means or a magneticmeans, including a permanent magnet attached to the surface of one ofthe plurality of cases and a magnetic member attached to the mating caseand able to be attracted by the permanent magnet.

The mechanical locking mechanism, however, has a complex construction,increases the cost of the small electronic apparatus, and in most cases,increases the weight of the small electronic apparatus. Also, amechanical locking mechanism having a simple construction typically andis easily broken.

The utilization of the magnetic attraction of a permanent magnet, forfixing the cases relative to each other, enables a retaining device foran electronic apparatus to be given a compact, lightweight, and durableconstruction at a reduced cost.

Recently, magnetic recording media, such as cash cards and floppy disks,have become widely used, but if such a magnetic recording medium isbrought into direct contact with the permanent magnet of a retainingdevice for an electronic apparatus, the magnetic data recorded on themagnetic recording medium is destroyed.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a low-costretaining device for an electronic apparatus capable of solving theproblems in the conventional retaining device for an electronicapparatus, employing magnetic attraction, having a compact, lightweightand durable construction, and eliminating the possibility of destroyingthe magnetic data recorded on a magnetic recording medium.

To achieve this object, the present invention provides a retainingdevice for an electronic apparatus comprising a plurality of casesrespectively containing individual component mechanisms of a smallelectronic apparatus, a magnet disposed in a recess formed in thesurface of the first case among the plurality of cases and a magneticmember provided on the second case among the plurality of cases,characterized in that the magnet attracts the magnetic member to fix therespective positions of the first case and the second case relatively toeach other when the first case and the second case are set contiguouslywith the magnet and the magnetic member disposed opposite to each other.

The magnet may be fixed to the first case.

The magnetic member may be movable between a projected position at whichthe magnetic member is projected from the surface of the second case anda recessed position at which the same is positioned below the surface ofthe second case, and the second case may be provided with a stopper forlimiting the length of the projection of the magnetic member from thesecond case to a value not greater than a predetermined value.

The magnetic member may be forced to project from the surface of thesecond case by a pushing means, and the magnetic member may be biased bya biasing means to be positioned below the surface of the second case.

The pushing means may be capable of being operated manually or thepushing means may be capable of automatically pushing the magneticmember so that the magnetic member projects from the surface of thesecond case when the first case and the second case are moved relativelyto each other and the magnet and the magnetic member are thus disposedopposite to each other.

A further magnetic member may be placed on the surface of the first casebetween the magnet and the surface of the first case, and the magnet canbe brought into contact with and separated from the further magneticmember.

The plurality of cases may be hinged by hinges.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary sectional view of a first embodiment in a joinedstate, according to the present invention;

FIG. 2 is a sectional side view of a printer incorporating the firstembodiment in an operating state;

FIG. 3 is a schematic plan view of the printer incorporating the firstembodiment in a carrying state;

FIG. 4 is a sectional side view of the printer incorporating the firstembodiment in a carrying state;

FIG. 5 is a rear elevational view of the printer of FIG. 3 in a carryingstate;

FIG. 6 is a bottom view of the printer of FIG. 2 in an operating state;

FIG. 7 is a perspective view of the printer incorporating the firstembodiment, in an operating state;

FIG. 8 is another perspective view of the printer of FIG. 2 whenexchanging a ribbon cassette;

FIG. 9 is a partly enlarged fragmentary sectional view of the firstembodiment, in a detached state;

FIG. 10 is a partly enlarged fragmentary sectional view of one part of asecond embodiment;

FIG. 11 is an enlarged fragmentary sectional view of the secondembodiment in a joined state;

FIG. 12 is a schematic view of a third embodiment in an unfolded, state;

FIG. 13 is a schematic view of the third embodiment in a folded state;

FIG. 14 is a schematic view of a fourth embodiment in an unfolded state;

FIG. 15 is a schematic view of the fourth embodiment in a folded state;

FIG. 16 is a view showing one type of permanent magnet; and

FIG. 17 is a view showing another type of permanent magnet.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be describedhereinafter with reference to the accompanying drawings.

Note, throughout the drawings, the same reference characters are used todesignate like or corresponding parts.

FIGS. 2 to 4 show a portable printer incorporating a retaining devicefor an electronic apparatus in a first embodiment according to thepresent invention. FIG. 2 shows the portable printer set in a folded andthus an operating state for printing, and FIGS. 3 and 4 show theportable printer in an unfolded and non-operating state, e.g., forcarrying, transportation or storage.

Referring to FIGS. 2 to 4, the portable printer has two individualcases, namely, a first case 1 and a second case 2. The two cases 1 and 2are hinged by hinges 3 so as to be able to turn relatively to eachother. The first case 1 contains a printing mechanism 10, a dry cell 50,and associated parts, and the second case 2 contains a sheet feedmechanism 20, a printed circuit board 30 provided with a controlcircuit, and associated parts.

As mentioned above, the printing mechanism 10 is contained in the firstcase 1. A flat platen 11 is placed in the first case 1, and a guideshaft 17 is fixedly placed so as to extend in parallel to the flatplaten 11. A carriage 13 supported for sliding movement on the guideshaft 17 is driven through a drive belt 16 by a stepping motor 15 forreciprocation along the guide shaft 17.

A print head 12 is mounted on the carriage 13 opposite to the platen 11,and a ribbon cassette 14 is detachably mounted on the carriage 13 sothat an ink ribbon 14a travels between the platen 11 and the print head12.

When the carriage 13 is driven by the stepping motor 15, the print head12 supported opposite to the platen 11 travels along the platen 11 forprinting characters.

The sheet feed mechanism 20 is contained in the second case 2. Threepairs of sheet feed rollers 21 and 22 are supported respectively onrotary shafts 21a and 22a in the second case 2. The drive roller 21 isdriven for rotation through rotary shaft a gear mechanism 26 in turndriven by a line feed motor 24.

The driven roller 22 is supported for rotation through rotary shaft 22aon arms 28 which turn on a shaft 27 in the second case 2. Rotary shaft22a is shown truncated in FIG. 3 for the sake of clarity. The arms 28are pressed by springs 29 in the direction of an arrow A (see FIG. 2),to press the driven roller 22 against the driving roller 21. The arms 28and the springs 29 are not shown in FIG. 3.

The printed circuit board 30 fixedly provided within the second case 2occupies a large space in the second case 2. Signals are transmittedthrough a flexible cable 31 to the stepping motor 15, the print head 12and the line feed motor 24 from the control circuits formed on theprinted circuit board 30. A main switch 45 of the portable printer isplaced in a recess formed in the second case 2, so as to be positionedbelow the surface of the second case 2.

The first case 1 and the second case 2 containing these mechanisms arehinged by the pair of hinges 3 at the opposite ends thereof, forrelatively turning on the hinges 3 such that they may be turned towardeach other and away from each other.

When using the portable printer, namely, when printing on a print sheet100 by the printing mechanism 10, the cases 1 and 2 are set with therespective wider surfaces 1a and 2a thereof joined together, as shown inFIG. 2. Hereinafter, this state of the portable printer will be referredto as a "folded state".

When the portable printer is not used, namely, when carrying ortransporting the portable printer, the portable printer can be openedthrough an angle of 180° so that the cases 1 and 2 extend in a plane asshown in FIGS. 3, 4, and 5. Since the cases 1 and 2 have substantiallythe same thickness, the portable printer can be opened to a flat shapeof a size corresponding to, for example, a size A4. Accordingly, theportable printer can be held under the arm or put in a bag, tofacilitate carrying and transporting the same, and the portable printercan be stored in a narrow space. This state of the portable printer willbe referred to as the "unfolded state".

A permanent magnet 32 is fixed to one of the outer side surfaces (bottomsurfaces in the folded state in FIG. 2) of the cases 1 and 2 that faceeach other in the unfolded state, and a steel plate 33 is fixed to theother outer surface. The permanent magnet 32 attracts the steel plate33, to hold the cases 1 and 2 in the unfolded state when the portableprinter is unfolded. The portable printer can be folded by applying aforce exceeding a certain level to the cases 1 and 2. Indicated at 35and 36 are feet joined respectively at locations 35a and 36a to thebottom surfaces of the cases 1 and 2, i.e., the bottom surfaces in thefolded state, so as to be turned through an angle of 90° (see FIG. 6).When not extended, the feet 35 and 36 lock in place with projections 35band 36b fitting in recesses 35c and 36c, respectively.

A sheet transporting passage 7 along which the print sheet 100 istransported is formed so as to extend straight through the cases 1 and 2in the folded state. The sheet transporting passage 7 is formed by slits7a and 7b formed in cases 1 and 2, respectively, as shown in FIG. 3. Asheet guide plate 43 is supported for turning on the second case 2 atthe inlet of the sheet transporting passage 7. The sheet guide plate 43can be opened to guide the print sheet 100 into the sheet transportingpassage 7 for printing.

The sheet transporting passage 7 extends straight and is inclineddownstream with respect to the sheet transporting direction. Therefore,the print sheet 100 can be smoothly discharged through an outlet 5formed in the first case 1 onto the surface 99 of a table (see FIGS. 2and 7).

In the folded state, the sheet feed mechanism 20 transports the printsheet 100 along the sheet transporting passage 7, and the printingmechanism 10 prints characters on the print sheet 100.

As can be seen in FIG. 8, a lid 44 is pivotally supported at its lowerend on the outer surface of the first case 1. The lid 44 is opened toexpose the ribbon cassette 14 in a large opening formed in the firstcase 1, to facilitate replacing a used ribbon cassette 14 with a newone. The outlet 5 is formed in the lower end of the lid 44.

Referring to FIG. 1 (and FIG. 9), a permanent magnet 60 and a steelplate (magnetic member) 62 are fixed respectively to the respectivewider outer surfaces 1a and 2a of the cases 1 and 2, which arecontiguous with each other in the folded state as shown in FIG. 2.

The permanent magnet 60 is placed in a recess 1b formed in the surfaceof the first case 1 and is attached to the first case 1. The permanentmagnet 60 is positioned below the surface of the first case 1, to avoiddirect contact of the permanent magnet 60 with a magnetic recordingmedium, such as a cash card or a floppy disk, in the unfolded state.

Furthermore, in this first embodiment, as can be seen in FIGS. 1 and 9,there is also provided a relatively larger square looped recess 1c onthe surface 1a of the first case 1, to a depth of about 0.5 mm, which isconcentric with the recess 1b, while retaining a frame or wall 1dsurrounding the recess 1b, which resembles a square looped partition(see FIG. 5).

The wall 1d, in addition to securing the position of the permanentmagnet 60 below the surface 1a of the first case 1, makes it is almostimpossible for a magnetic recording medium (not shown) which for exampleslides on a flat surface of the square looped recess 1c, to come intodirect contact with the permanent magnet 60 within the frame or wall 1dat the most important magnetic recorded portion thereof.

Further, it is not essential for the wall 1d to be continuous around therecess 1b.

The steel plate 62 is placed in a recess 2b formed in the surface 2a ofthe second case 2 so as to be located opposite to the permanent magnet60 in the folded state. When in the folded state as shown in FIG. 1, thepermanent magnet 60 attracts the steel plate 62.

A stem 63 attached to the steel plate 62 is fitted loosely for axialmovement in a hole formed in the central portion of the recess 2b of thesecond case 2. The extremity of the stem 63 is situated within thesecond case 2. A second stem attached to a spring bearing plate 64having a large diameter is fixedly joined to the extremity of the stem63.

A compression coil spring 65 having a comparatively small springconstant is extended between the spring bearing plate 64 and the secondcase 2, to bias the spring bearing plate 64, the stem 63 and the steelplate 62 integrally toward the interior of the second case 2.

When the cases 1 and 2 are not in the folded state, as shown in FIG. 9,the steel plate 62 is retracted into the recess 2b by the compressioncoil spring 65, so that the surface of the steel plate 62 issubstantially flush with or positioned slightly below the surface of thesecond case 2, to avoid damage to other objects.

When the cases 1 and 2 are set in the folded state as shown in FIG. 1,the permanent magnet 60 attracts the steel plate 62 against theresilience of the compression coil spring 65, so that the steel plate 62projects from the surface of the second case 2.

If an external separating force is applied to the cases 1 and 2 in thefolded state, the steel plate attracted to the permanent magnet 60 ispulled out from the second case 2 until the spring bearing plate 64 isbrought into contact with a stopper 67 formed in the second case 2.Since the steel plate 62 is unable to project any further, therespective positions of the cases 1 and 2 relative to each other arefixed by the magnetic attraction acting between the permanent magnet 60and the steel plate 62.

If an external force exceeding the magnetic attraction between thepermanent magnet 60 and the steel plate 62 is applied to the cases 1 and2, the steel plate 62 is separated from the permanent magnet 60, andthen the steel plate 62 is retracted into the recess 2b of the secondcase 2 by the resilience of the compression coil spring 65.

Accordingly, the cases 1 and 2 are allowed to freely turn on the hinges3, away from each other.

FIGS. 10 and 11 show a retaining device for an electronic apparatus in asecond embodiment according to the present invention. This retainingdevice for an electronic apparatus is provided with a push button 68that is operated by hand to forcibly push out a steel plate 62 from arecess 2b formed in a second case, against the resilience of acompression coil spring 65.

The front end of the push button 68 is in contact with the back surfaceof a spring bearing plate 64, and when pushed, the push button 68 pushesthe spring bearing plate 64 against the resilience of the compressioncoil spring 65. The head 68a of the push button 68 is placed in a recess2c formed in the second case 2 opposite to the recess 2b so that thehead 68a is positioned below the surface of the second case 2 and can bereached from the outside.

Note, the permanent magnet 60 is positioned well below the surface 1a ofthe first case 1, to thus prevent any possible leakage of the magneticflux from the recess 1b, and the steel plate 62 is kept stable in therecess 2b below the surface 2a of the second case 2, as shown in FIG.10.

Accordingly, in this condition, when the cases 1 and 2 are joinedtogether in the folded state, the permanent magnet 60 can not come intocontact with the steel plate 62.

To solve this problem, there is provided the push button 68 andassociated parts.

In this case, the push bottom 68 is depressed with the finger tip topush the steel plate 62 forcibly out of the recess 2b to a point atwhich the steel plate 62 is brought into close contact with thepermanent magnet 60, as shown in FIG. 11. Then, the steel plate 62 isattracted to the permanent magnet 60 and, consequently, the first case 1and the second case 2 are fixed relative to each other. The rest of theparts and construction of the retaining device for an electronicapparatus in the second embodiment are the same as those of theretaining device for an electronic apparatus in the first embodiment.

FIGS. 12 and 13 show a third embodiment of the present invention. Thethird embodiment is provided with a cam 3c formed on the outer surfaceof a hinge 3, and a flat spring 71 fixedly holding a steel plate 62 andhaving a free end engaging the cam 3c.

The flat spring 71 is provided within a second case 2. In the unfoldedstate, the free end of the flat spring 71 is pushed by the cam 3c, sothat the flat spring 71 is strained in a large curvature to hold thesteel plate 62 positioned below the surface of the second case 2 asshown in FIG. 12. A permanent magnet 60 is fixed to a first case so thatthe same is positioned below the surface of the first case 1.

When the cases 1 and 2 are joined together in the folded state, the freeend of the flat spring 71 is disengaged from the cam 3c and thecurvature of the flat spring 71 is reduced as shown in FIG. 13.Consequently, the steel plate 62 projects from the surface of the secondcase to enable the permanent magnet 60 to attract the steel plate 62.

Thus, in this third embodiment, the steel plate 62 is projected from andretracted into the second case automatically, according to the movementof the second case 2 relative to the first case 1.

FIGS. 14 and 15 show a fourth embodiment of the present invention. Amovable arm 82 is supported pivotally in a first case 1 and is biasedclockwise by a torsion spring 81. A permanent magnet 60 is secured tothe free end of the movable arm 82. The permanent magnet 60 can bebrought into contact with and separated from a yoke (magnetic member) 83having one end exposed outside.

In this embodiment, an elongated rod 84 connected to a hinge 3 supportsthe movable arm 82, to keep the permanent magnet 60 separated from theyoke 83 as shown in FIG. 14 in the unfolded state. Accordingly, articlesoutside the first case 1 are not affected by the magnetic field of thepermanent magnet 60 in the unfolded state.

When the cases 1 and 2 are joined together in the folded state, as shownin FIG. 15, the rod 84 is pulled down as the hinge 3 turns and releasesthe movable arm 82. Then, the torsion spring 81 turns the movable arm 82to bring the permanent magnet 60 into contact with the yoke 83 and,consequently, a steel plate 62 fixed to the second case 2 is attractedto the yoke 83 by the magnetism of the permanent magnet 60.

Thus, in the fourth embodiment, the permanent magnet 60 provided withinthe first case 1 comes into contact with and separates from the yoke 83according to the movement of the first case 1 relative to the secondcase 2. Therefore, in the unfolded state, articles outside the cases 1and 2 are not affected by the magnetic field of the permanent magnet 60.

The present invention is by no means limited to the specific embodimentsas illustrated and described herein, and it is clear that variousmodifications thereof may be made which come within the scope of thepresent invention as defined in the appended claims.

In the foregoing embodiments, for example, the magnet and the magneticmember may be interchanged. In any case, the permanent magnet 60 must bepositioned below the surface of the case 1 or 2 and, preferably, thesteel plate 62 does not project from the surface of the case 2 or 1 inthe unfolded state.

The present invention is applicable to various electronic apparatusesincluding personal computers and word processors, as well as theportable printer.

Further, the following description encompasses various modifications ofthe permanent magnet 60, with reference to FIGS. 16(a), 16(b), 17(a) and17b). FIGS. 16(b) and 17(b) are side views of FIGS. 16(a) and 17(a),respectively.

The flat rectangular magnet of FIGS. 16(a) and 16(b) has the usualmagnet pole arrangement, the center portion of which has smallermagnetic attraction.

On the other hand, the magnet of FIGS. 17(a) and 17(b) is of the sameshape as that of FIGS. 16(a) and 16(b), but has 4 magnetic poles on bothsides. It is preferable to use the latter type rather than the former,as a smaller leakage of the magnetic flux from the recess occurs whenthe latter type is used.

From the foregoing, it can be seen that the retaining device for anelectronic apparatus in accordance with the present invention fixes theplurality of cases relative to each other by the magnetic attraction ofthe magnet, and thus the retaining device for an electronic apparatuscan be readily given a compact, lightweight and durable construction ata reduced cost. Since the magnet is positioned below the surface of thecase, magnetic data recorded on a magnetic recording medium cannot bedestroyed when the magnetic recording medium is brought into contactwith the case.

We claim:
 1. A retaining device, comprising:first and second casespivotally connected along respective lateral edges thereof for beingselectively pivoted between open and closed positions relatively to eachother; a magnet positioned in a recess formed in a surface of the firstcase so that at least when the first and second cases are in the openposition, the magnet cannot damage a magnetic recording medium locatedwithin the proximity of the surface of the first case; a magnetic memberprovided on the second case in a position complementary to the positionof the magnet in the first case, at least one of the magnet and themagnetic member being movable to an operating position when the firstand second cases are in the closed position so as to be mutuallyattracted and thereby to produce a magnetic force which assists inmaintaining the first and second cases in the closed position; and afurther magnetic member provided on the surface of said first case, saidmagnet being selectively brought into contact with and separated fromthe further magnetic member and the further magnetic member beingpositioned so that when the magnet is in contact with the furthermagnetic member and the first and second cases are in the closedposition, the further magnetic member is disposed generally intermediatethe magnet and the magnetic member.
 2. A retaining device according toclaim 1, wherein said magnet is fixedly attached to the first case.
 3. Aretaining device according to claim 1, wherein said magnetic member ismoved selectively to a projected position at which the magnetic memberprojects from a surface of the second case and a recessed position atwhich the magnetic member is positioned below the surface of the secondcase.
 4. A retaining device according to claim 3, wherein said secondcase is provided with a stopper for limiting the extent of theprojection of the magnetic member from the surface of the second case toan amount not greater than a fixed amount.
 5. A retaining deviceaccording to claim 3, further comprising pushing means for pushing themagnetic member from the recessed position to the projected positionwhereby the magnetic member is forced to project from the surface of thesecond case.
 6. A retaining device according to claim 3, furthercomprising biasing means for biasing said magnetic member to therecessed position below the surface of the second case.
 7. A retainingdevice according to claim 5, wherein said pushing means is manuallyoperable.
 8. A retaining device according to claim 5, wherein saidpushing means automatically pushes said magnetic member to the projectedposition and so that said magnetic member projects from the surface ofthe second case when the first case and the second case are movedrelatively to each other to the closed position and said magnet and saidmagnetic member are thus disposed opposite to each other in thecomplementary positions thereof.
 9. A retaining device according toclaim 1, wherein said magnet automatically contacts said furthermagnetic member when the first case and the second case are pivoted tothe closed position.
 10. A retaining device according to claim 2,wherein said magnetic member is movable selectively to a projectedposition at which the magnetic member projects from a surface of thesecond case, as the operating position, and to a recessed position atwhich the magnetic member is positioned below the surface of the secondcase.
 11. A retaining device according to claim 4, further comprisingpushing means wherein the magnetic member is forced to project from thesurface of the second case by said pushing means.
 12. A retaining deviceaccording to claim 4, further comprising biasing means wherein saidmagnetic member is biased by biasing means to be positioned below thesurface of the second case.
 13. A retaining device according to claim 5,further comprising biasing means wherein said magnetic member is biasedby biasing means to be positioned below the surface of the second case.14. A retaining device according to claim 5, further comprising biasingmeans wherein said magnetic member is biased by biasing means to bepositioned below the surface of the second case.
 15. A retaining deviceaccording to claim 6, wherein said pushing means is manually operable.16. A housing for an electronic printer, comprising:first and secondcases having first and second, parallel and spaced main surfaces ofsubstantially the same rectangular configuration and size and being of asubstantially common thickness as defined by the spacing between therespective first and second main surfaces thereof, the first and secondcases being pivotally connected along corresponding lateral edges of therespective first main surfaces thereof; the first and second cases beingselectively pivotable between the open and closed positions relativelyto each other, the first and second main surfaces of the first andsecond cases lying in substantially common and respective first andsecond parallel planes in the open position of the first and secondcases and the respective first main surfaces of the first and secondcases being disposed in contiguous relationship and the respectivesecond main surfaces of the first and second cases correspondingly beingdisposed in parallel relationship and spaced apart by the combinedthicknesses of the first and second cases in the closed, operatingposition thereof; the first and second cases respectively containingtherewithin corresponding first and second portions of the printer,including respective first and second portions of a sheet feeding means,respectively defining first and second sheet feed path portions, forfeeding a sheet through the respective first and second sheet feed pathportions for printing on the sheet; the first and second cases furtherhaving slots defined in the respective first and second main surfaceportions thereof in alignment with the corresponding first and secondsheet feed path portions and the corresponding openings in the first andsecond main surfaces of the respective first and second cases beingaligned in the closed, operating position of the first and second casesand thereby defining a continuous sheet feed path extending from thesecond main surface of one and to the second main surface of the otherof the first and second cases in the closed, operating position thereof;a magnet positioned in a recess formed in a surface of the first case sothat at least when the first and second cases are in the open position,the magnet can not damage a magnetic recording medium located within theproximity of the surface of the first case; and a magnetic memberprovided on the second case in a position complementary to the positionof the magnet in the first case, at least one of the magnet and themagnetic member being selectively movable to an operating position whenthe first and second cases are in the closed position so as to bemutually attracted and thereby to produce a magnetic force which assistsin maintaining the first and second cases in the closed, operatingposition and thereby defining the continuous sheet feed path.
 17. Ahousing according to claim 16, wherein:the magnet is positioned in arecess formed in the first main surface of the first case; and themagnetic member is provided in a recess in the first main surface of theother of the second case and at a position complementary to the positionof the magnet and such that the magnetic member is aligned with themagnet in the closed position of the first and second cases.
 18. Ahousing according to claim 17, wherein said magnetic member is movableselectively from a retracted position within the recess and below thecorresponding first main surface of, and thereby within, the first case,to a position projecting from the first main surface in the operatingposition thereof and so as to be mutually attracted to and contacted bythe magnet.
 19. A housing according to claim 18, furthercomprising:biasing means for biasing the magnetic member to theretracted position within the recess.
 20. A housing according to claim19, further comprising:means for automatically forcing the magneticmember to the projecting position when selectively moving the first andsecond cases to the closed, operating position.
 21. A housing accordingto claim 19, further comprising:means, manually operable, for forcingthe magnetic member to the projecting position in the closed position ofthe first and second cases.